180 is much too low. I never print pla at less than 200 and usually 210c.
A higher temperature will improve layer adhesion and make your prints much stronger. Plus it also sticks better

The glass plate is probably your best bet as it should be level. Does not matter if the original bed is not level, heat transfer won't be sufficiently effected to worry about. Worst case scenario, set it for 60c rather than 50.
For pla it really isn't that critical.

Something else you can do to offset a warped buil;d plate is make the first layer really thick. 0.4mm is most likely the most you can go to. make it thick and put it down very slow and that can over ride a slightly uneven plate. Like a raft does, but without the time and waste a raft entails.

And have patience, there aren't actually that many of us who bother to answer questions and we don't live online, much as it might seem I do ;-)